We have shown that, despite their increased glycolytic muscle fiber composition, myostatin deficient mice are able to perform endurance exercise without incurring muscle damage. Myostatin deficient mice are able to successfully adapt to endurance exercise by increasing oxidative enzyme activity. Myostatin deficient mice do, however, have a decrease in overall exercise capacity. We have also analyzed gene expression changes in gastrocnemius skeletal muscle with and without myostatin inhibition in a model of diabetes to determine the molecular mechanisms of myostatin regulation of muscle metabolism at the molecular level.